Former White House press secretary and Obama adviser Robert Gibbs said in an interview Sunday that his bosses told him not to discuss the government's targeted drone strikes against suspected terrorists in countries like Pakistan, or even acknowledge its existence.

"When I went through the process of becoming press secretary, one of the first things they told me was, 'You're not even to acknowledge the drone program. You're not even to discuss that it exists,'" Gibbs said on MSNBC on Sunday.

During much of President Obama's first term, the administration denied that the drone program existed, and continued to withhold information about it until last year.

"Here's what's inherently crazy about that proposition: you're being asked a question based on reporting of a program that exists. So you're the official government spokesperson acting as if the entire program … pay no attention to the man behind the curtain," added Gibbs, who is now an MSNBC contributor.

Gibbs suggested the lack of transparency wasn't a wise decision. "I think you've seen recently the president discuss the need and desire to be more forthcoming," he said. "I have not talked to him about this, so I want to be careful, this is my opinion, but I think what the president has seen is, our denial of the existence of the program when it's obviously happening undermines people's confidence overall in the decisions that their government makes."

Obama counter-terrorism adviser John Brennan acknowledged the use of drones for the first time in April last year. That decision, Gibbs added, may have helped boost public confidence in the drone program. "In order to bolster that confidence and bolster the belief that we're making those correct decisions on this policy, you do have to lift the veil some," he said, "to both acknowledge that it exists, as he's done, but also to do it in a way that provides better understanding."

According to reports, the use of unmanned drones has increased over the last four years from Pakistan to Yemen. Critics say it can potentially kill civilians and lacks due process of law.

The policy of secrecy, Gibbs said, gave him a tough time dealing with reporters. He cited an exchange in 2009 with Major Garrett, then of Fox News, saying, "I would get a question like that and literally I couldn't tell you what Major asked, because once I figured out it was about the drone program, I realize I'm not supposed to talk about it."

According to the Bureau of Investigative Journalism, about 300 strikes have been launched in Pakistan since 2004, up to 50 in Yemen since 2002, and between around nine in Somalia since 2007.